JPS6042458B2 - printing device - Google Patents

Description

[Detailed description of the invention] 〔Technical field〕 The present invention relates to intermediate devices.

[Prior art]

Figure 1 shows the configuration of an intermediate device using a liquid crystal light valve.

Optical writing is performed on the photosensitive drum 102 by an optical signal generating section 101 consisting of a liquid crystal light valve. At this time, the photosensitive drum 102 is charged in advance by a corona charger 110. The optical signal at this time usually includes, for example, characters, in which light is generated corresponding to the part of the characters. As a result, an electrostatic latent image is formed, and the magnetic brush developer 103-
Developed with toner. The developing method at this time is usually reversal development. Thereafter, the toner is transferred onto plain paper 104 by a transfer corona discharger 105 and fixed by a fixing device 106. Toner remaining on the photosensitive drum after transfer is
The electrostatic latent image is removed by the blade 108 and the electrostatic latent image is removed by the defrost lamp 10.
Defrosting is completed at 9. FIG. 2 shows the configuration of the optical signal generator.

The optical signal generating section consists of a light source 111 such as a fluorescent lamp, a liquid crystal light valve 150, and an imaging lens 115. The liquid crystal light valve 150 consists of a liquid crystal panel 112 and a liquid crystal drive circuit 113, and is mounted on a mounting board 114. . The light emitted from the light source is modulated by a liquid crystal light valve. This optical signal 116 is transmitted to the photosensitive drum 10 by an imaging lens 115.
The image is formed on 2. An erect image can be obtained by using a focusing optical fiber array as the imaging lens. FIGS. 3 and 4 show the structure of the liquid crystal panel. The LCD panel is
Glass substrate 11 with common signal electrodes 119 and 120
7 and a glass substrate 11 comprising signal electrodes 121 and 122.
8 and spacer 126, and polarizing plates 123 and 124 are placed on both sides of the glass substrate.
It consists of: The common signal electrode consists of a transparent electrode 119 and an optically opaque metal electrode 120, and the signal electrode 121
and 122 are transparent electrodes. The polarizing plates 123 and 124 are arranged so that their polarization planes are perpendicular to each other. The light is modulated by a microshutter formed by the transparent portion 119 of the common electrode and the signal electrode. In the text below, there are parts where the shape of the transparent part of the common electrode is expressed as a microshutter, but in this case, please interpret it as forming a microshutter together with the opposing signal electrode.
The liquid crystal composition to be sealed is disclosed in Japanese Patent Application No. 55-14108.
The optically active substance 4-(2-Methy) is added to the nematic liquid crystal of
Ibutyl)-4″-CyarK)Biphenyl
By using a long-period cholesteric liquid crystal obtained by adding 3% by weight of s, a high-speed liquid crystal light valve can be obtained. FIG. 5 shows the frequency characteristics of the dielectric anisotropy of this liquid crystal. The frequency at which the dielectric anisotropy is zero is called the crossover frequency and is expressed as fl. Let n1 be the frequency lower than FC, and Fh be the higher frequency. The liquid crystal light valve operates by applying signals of frequencies f1 and Fh to each signal electrode. FIG. 6b shows the response of the applied signal and the light transmitted through the liquid crystal light valve a. At time T2, the signal 1 is applied, and the signal Fh at time T3 is applied.

T1 is called a writing period, T2 is called an opening time, and T3 is called a non-opening time. The liquid crystal light valve opens by applying the Fh signal and closes by the fl signal. By the method described above, we were able to obtain a revolutionary high-speed liquid crystal light valve. However, in such conventional technology, when the moving speed of the photoreceptor of the printing device changes, for example, when high-speed printing is desired even if there is some decrease in resolution,
On the other hand, there was a problem in that it could not be used in cases where printing with high resolution was desired even if the speed was somewhat slow. [Purpose] The present invention has a three-digit common electrode, and by devising the arrangement of the micro-shutter array, the printing speed is twice as fast as that of a conventional printing device using a liquid crystal light valve. An object of the present invention is to provide a liquid crystal light valve that can be used in a printing device that can arbitrarily select two modes for obtaining high tactile force.

〔Example〕

FIG. 7 shows the electrode structure of a liquid crystal panel according to the present invention.

The difference from the conventional example shown in Fig. 4 is that the common electrode is 401.
, 402, and 403, and three microshutters 406, 407, and 408 for one signal electrode 404. Next, the driving method, which is the main point of the present invention, is shown in FIGS. 8 and 9.

A dedicated 1C with high breakdown voltage is used to drive the liquid crystal, but in the present invention, by performing 112 time-division drives, the number of drive 1Cs is not increased, and the reliability of high-density packaging is greatly improved. It produced an improvement effect. 9th
The figure shows the configuration of electrodes for explaining the principle of the time-division driving method of 112.
23, micro shutters 424 and 425 are driven.

The signals to be applied are shown in Fig. 8.
The common electrodes each take charge of the time Ta as a selection period. An 0N signal 410 and an 0FF signal 411 are applied as data signals to the signal electrode during the period Ta. 0
The N signal 410 is a high frequency signal Fh, . The period T3 consists of a low frequency n, and the 0FF signal 411 has a low frequency f1.

The common electrode signal 412 is composed of a signal having a phase opposite to that of the 0N signal 410 during the selection period, and a signal having a phase opposite to the 0FF signal 411 during the non-selection period, and the common electrode signals applied to the two common electrodes have different phases. It's half a cycle off. For example,
If the common electrode signal 412 is applied to the common electrode 421, and the T1 PN signal and 0FF signal are applied to the signal electrode 423, the signals applied to the micro shutter 424 will be 413 and 414, respectively. The optical responses as micro shutters are 415 and 416, respectively.

As shown here, the liquid crystal light valve in the present invention is
/■ Light is transmitted only when high frequency is applied to both the electrode and the signal electrode. The present invention is based on the above principle. A single liquid crystal light valve with double speed and double density modes will be explained with reference to FIG. First, when in double density mode, the seventh
The common electrode signal 4 is applied to the common electrodes 401 and 402 in the figure, respectively.
30 and 431 are applied to the common electrode 403, and a low frequency wave 432 having an opposite phase to the 0FF signal is applied to the common electrode 403. Then, when a signal 433 corresponding to the data is applied to the signal electrode 404, the micro shutters 406, 407, and 408 each receive a signal 433 corresponding to the data.
4,435,436 voltages are applied, and as described above, the microshutters 406, 407 are opened and closed during selected periods, respectively, according to the data signal. On the other hand, the microshutter 408, to which only low frequency waves are always applied to the common electrode 403, remains completely closed. Therefore, at this time, it is as if there is no row of microshutters 404, and writing is performed using only two rows of microshutters 406 and 407. Micro shutters 406 and 407
are arranged in a staggered manner, and one line of printing is performed using two rows of micro shutter arrays. Now, the interval between the micro shutters 406 and 407 is 11, and the writing cycle is T1.
, if the photoreceptor moves at a speed V in the direction of the arrow in FIG.
Since the opening and closing will be repeated every 12T, in order for the written adjacent dots to line up on a straight line, 11 = (
m+112) TlV (m=0, 1, 2...) must be satisfied. Next, in the double speed mode, a low frequency wave 432 is applied to the common electrode 401, and the common electrode 402
, 403, and common electrode signals 430 and 431, respectively.

Therefore, the micro-shutter array 406 is now closed, and writing is performed using the micro-shutters 407 and 408. The microshutters 407 and 408 are located on the same line in the direction of movement of the photoreceptor, and print one line alternately. Therefore, in double density mode, 1 at time T1
In contrast to writing a line, in the double speed mode, two lines are written in the time T1, and the density of one dot becomes half as coarse, so the photoreceptor movement speed is actually 4 mm.
In other words, it is possible to write at four times the speed of double density mode. Therefore, if the moving speed of the photoreceptor in the double density mode is V, then the distance between the microshutters 407 and 408 is 12
is 12=4nVT1 (n=1, 2, 3, etc.).Next, an embodiment and a driving circuit will be described.

In this invention, 16.7 dots/? and 8.3 dots/
Try the order. Made. The repetition period T1 is 2n1sec, so ■ = 3C1n/Sec Considering the ease of manufacturing the panel, m = 2 and n = 12, so 11 = 150I, respectively.
Lm,12=240pm. FIG. 11 shows the drive circuit. Selector 501 selects double-density and double-speed mode. conduct. A data request lock is sent from the control unit 502 to the external time-series pixel signal generation unit 510 every 2 msec in the double-density mode and every 1 msec in the double-speed mode, and the data selector 503 receives data synchronized with the request clock.・Take it away. In the double-density mode, one line of received data is divided into two parts, one of which is distributed to the shift register 505 and the remaining part to the data buffer memory 504. The data stored in the memory 504 is delayed by two cycles and sent to the shift register 505 alternately every half cycle with the data directly output from the data selector. After the data entered in the shift register 505 is transferred, it is latched by a latch 506, and the signal selector outputs an 0N signal 511 according to the latched data.
Alternatively, the 0FF signal 512 is output. In the double speed mode, input data is alternately sent one line at a time, data is sent as is to the shift register 505 and data is sent to the memory 504, and data delayed by 2 rnsec and data not delayed are alternately transferred to the shift register 504. , one line is written at a speed of 1 msec.

508 is a signal generation section, which generates 0N signal 511, 0FF signal 5
12. Generate common electrode signals, etc.

The printing system other than the optical writing section has two process speeds, and the speeds are switched between V and 4V depending on the mode selection.

〔effect〕

As described above, the present invention has a 1-digit microshutter array and a 2-digit microshutter array.
The micro-shutter rows of digits 1 and 2 are arranged in a staggered manner, and the micro-shutter rows of 3 digits are arranged parallel to the micro-shutter rows of 1 or 2 digits in parallel to the moving direction of the photoreceptor. Because of the structure, two cs of double speed or double density
This has the effect of making it possible to arbitrarily select m.

[Brief explanation of drawings]

FIG. 1 shows an example of the configuration of a printing device using a liquid crystal light valve. FIG. 2 shows an example of the configuration of an optical signal generator using a liquid crystal light valve. 3 and 4 show the structure of the liquid crystal panel. FIG. 5 shows the frequency characteristics of dielectric anisotropy of the liquid crystal material used in the present invention. FIG. 6 shows the response characteristics of the liquid crystal material used in the present invention and the driving signals at that time.
FIG. 7 shows the structure of a liquid crystal panel having a double speed and double density mode according to the present invention. FIG. 8 shows the drive waveform and optical response of the time-division drive method adopted in the present invention. FIG. 9 shows an electrode configuration for time-division driving. FIG. 10 shows drive waveforms for realizing the double-speed, double-density mode of the present invention. FIG. 11 shows a drive circuit according to the present invention. 101・
... Optical signal generating section, 102 ... Photosensitive drum, 10
3...Developer, 105...Transfer device, 1
06... Fixing section, 110... Charger, 1
DESCRIPTION OF SYMBOLS 11...Light source, 112...Liquid crystal panel, 113...Drive circuit, 115...Imaging lens, 401...Common electrode 1, 402...
...Common electrode 2, 403...Common electrode 3, 4
04... Signal electrode, 406, 407, 408.
...Micro shutter.

Claims (1)

[Claims] 1 A liquid crystal is sealed in a pair of transparent substrates, three common electrodes are formed on one side of the substrates, and a plurality of signal electrodes are formed on the other side, and each signal electrode is arranged to cross the common electrodes. As a result, in a printing device having a photoreceptor that moves in a direction perpendicular to the longitudinal direction of a common electrode and a liquid crystal light valve in which a three-digit number of micro-shutters are formed, a one-digit micro-shutter row and two micro-shutter arrays can be used. The micro-shutter rows in the digit number are arranged in a staggered manner, and the micro-shutter rows in the digit number 3 are arranged in parallel with the micro-shutter rows in the digit number 1 or 2 with respect to the moving direction of the photoreceptor. A printing device.